This invention pertains to wind turbines, and more particularly, to wind turbines having a turbine wheel containing a plurality of airfoils which is mounted for revolution on a cantilevered carriage.
Many types of wind-powered generators have been developed in order to provide a source of energy which does not use expendable or radioactive natural resources. These generally are in the form of wind turbines. One wind turbine design which has been developed includes a large turbine wheel having a generally circular rim with airfoils distributed circumferentially about a hub internally of the rim. The wheel is generally supported by an axle extending through the hub, which axle is then supported relative to a foundation. Power is taken off of such wheels by various means such as a generator the rotating axle, by a belt which extends around the turbine rim and a pulley connected to a generator, or by a rack mounted on the rim which drives a pinion connected to a generator. Alternatively, the wheel may be supported on one or more power take-off wheels connected to generators.
In this latter design, the power take-off wheels are mounted on a carriage which rides on a circular track extending around a central structure connected to the hub of the turbine wheel. In order to keep such turbine wheels stable on the carriage, one known method is to provide extended axles projecting axially from the hub with guy wires connected to the wheel near the rim. These devices are usually freely riding on the circular rail so that the wind forces them to align downwind from the center pivot.
It can be seen that in order to install such a device, an elaborate foundation must be provided to support the carriage track so that it is substantially horizontally disposed and circular. The topographical locations which are suitable for its installation are very limited. Further, when suitable areas are available, each wind turbine installation occupies a substantial amount of area. Further, some inefficiencies result in such systems by the wind shadow that results from having the center pivot structure upwind from the turbine during operation.
The present invention provides a carriage-supported wind turbine wheel which avoids the above disadvantages. In particular, it provides a wind turbine which does not require the use of a track for the carriage to ride on and does not require the use of extended axles with guy wires for maintaining the turbine wheel in an upright position.
These and other advantages are obtained in a wind turbine made according to the present invention which includes a cantilevered support for a carriage on which the turbine wheel rides. The carriage is cantilevered from a centrally disposed anchoring assembly which, in a preferred embodiment, is disposed along an axis of revolution of the carriage. Thus, only a central foundation is required for supporting the entire wind turbine. Further, a driver positions the wind turbine wheel upwind from the central anchoring assembly, with no structural supports upwind of the wind turbine wheel, so that the airfoils of the wheel receive the direct impact of the wind. Further, the wheel is held in a stable position on the carriage by a short axle and a truss system which also supports the airfoils. The axle is connected to a pylon in a manner allowing rotation and revolution of the turbine wheel. Further, the axle and wheel pivot about an axis which is generally parallel to the plane of the wheel, thereby allowing essentially the full weight of the wheel to be supported on the carriage.
These and additional features and advantages of the present invention will be more clearly understood from a description of the drawings and a detailed description of the preferred embodiment.